I watch tutorials to understand new concepts, so I watch the whole thing. Many times if needed. If I grabbed the idea, I might try to apply what I learned, but I will not watch along.
Many people making tutorials are like I just do it to explain, but you should pay more attention to how to make that part and do not apply good programming concepts, which is very bad in my opinion.
In my mind, because it's a tutorial, you should code properly every single line of code, it'll be more beneficial...